体性感覚 Somatosensory System
P3-1-140 小児における外国語音産出能力と脳形態の相関について Relationship between brain anatomy and an ability of non-native speech sound production in school children ○橋爪寛1, 瀧靖之1,2佐々祐子1, 浅野路子1, 浅野孝平1, 竹内光1杉浦元亮1,3, 川島隆太1 ○HIROSHI HASHIZUME1, Yasuyuki Taki1,2, Benjamin Thyreau1, Yuko Sassa1, Michiko Asano1, Kohei Asano1, Hikaru Takeuchi1, Hyeonjeong Jeong1, Motoaki Sugiura1,3, Ryuta Kawashima1 東北大学 加齢医学研究所1, 東北大学 東北メディカル・メガバンク機構2, 東北大学 災害科学国際研究所3 Institute of Development, Aging and Cancer, Tohoku University, Sendai1, Tohoku Medical Megabank Organization, Tohoku University, Sendai2, International Research Institute of Disaster Science, Tohoku University, Sendai3 There is a large individual difference in an ability of non-native speech (L2) production. A previous study has shown a relationship between brain anatomy and the ability in adults. Adults who were better than others at producing L2 had greater white matter density in the posterior left inferior frontal gyrus (L-IFG) and inferior parietal lobule (IPL), which were a part of the regions known to activate during L2 production. Here, we examined the anatomical correlates of L2 production in school children, whose ability of L2 production known to be different from adults.38 healthy, native Japanese children participated in this study. They were monolingual, right-handed, 6- to 18-year-old. All subjects and their parents gave informed consent to participate in the study, which was approved by the institutional review board of Tohoku University School of Medicine. L2 production ability of each participant was measured (L2 production score, L2PS) based on utterances of 16 unfamiliar non-native syllables. We conducted voxel-based morphometry analysis using high-resolution anatomical magnetic resonance imaging. Then, we analyzed the correlation of the regional gray (rGMV) or white (rWMV) matter volumes and L2PS. To narrow our focus on brain regions that activate during non-native speech production, anatomical regions activated during L2 production were selected as regions-of-interest (ROIs), including L-IFG and L-IPL.We found significant positive correlations between rWMV and L2PS in L-IPL and between rGMV and L2PS in the right middle frontal gyrus (R-MFG) (P<0.05, family-wise error correction for multiple comparison with small volume correction). More rWMV in L-IPL in children who were better at L2 production is consistent with the previous adult study. Our results suggest that the involvement of R-MFG, which was not seen in the adult study, might facilitate elaborated L2 production in children, and result in the difference in the ability between children and adult.	P3-1-141 電気刺激と感覚刺激はマウス一次感覚ニューロンにおいてNF-κBのリン酸化と核移行を起こす Electrical and sensory stimuli induce nuclear translocation and phosphorylation of nuclear factor kappa B in primary sensory neurons of mice ○松村潔1, 藤川愛2, 伊吹京秀2, 西川典浩3, 小林茂夫4 ○Kiyoshi Matsumura1, Megumi Fujikawa2, Takae Ibuki2, Norihiro Nishikawa3, Shigeo Kobayashi4 大阪工業大・工・生命工学1, 京都府立医科大院・麻酔科2, 大阪工業大・情報科学3, 京都大学院・情報学4 Dept Biomedical Engineering, Osaka Institute of Technology, Osaka1, Dept Anesthesiology, Grad Sch Med Sci, Kyoto Prefectural Univ of Medicine, Kyoto2, Faculty of Information Sci and Engineering, Osaka Institute of Technology, Osaka3, Grad Sch of Informatics, Kyoto Univ, Kyoto4 Nuclear factor kappa B (NF-κB) is a transcription factor, which is translocated to the nucleus when activated in various types of cells. Herein, we demonstrate immunohistochemically that electrical, chemical, and thermal stimuli, applied to the skin of mice, all induced nuclear translocation and phosphorylation of NF-κB in dorsal root ganglia (DRG) neurons. All experiments were done in C57BL/6 mice under pentobarbital anesthesia. Sine-wave current of 1 mA was applied to the right hindpaw at a frequency of 5 Hz or 2000 Hz for 3 min. Just after the stimulation, mice were killed by transcardiac perfusion of 4% lidocaine-HCl. Vertebral bones containing DRG and spinal cord were excised and frozen. DRG sections were stained immunohistochemically using anti-phospho-NF-κB antibody. Both frequencies of electrical stimuli induced nuclear translocation of phospho-NF-κB in the right L3/L4 DRG neurons. Electrical stimulation at 5 Hz evoked the response preferentially in small-size neurons compared to that at 2000 Hz being in line with electrophysiological findings reported previously. Similarly, chemical stimulus with 5% formalin injected subcutaneously to the right hindpaw induced nuclear translocation of phospho-NF-κB in the right L3/L4 DRG neurons. As the thermal stimulus, the scrotum was warmed and kept between 37°C and 39°C for 10 min. Phospho-NF-κB-positive neurons were observed in L6 DRG. Few nuclear phospho-NF-κB-positive neurons were observed in DRG innervating unstimulated regions. These results suggest somatosensory stimuli quickly induce NF-κB-mediated gene transcription in DRG, and phospho-NF-κB could be a suitable histological marker for activated DRG neurons.
P3-1-142 血流遮断によるしびれの脊髄メカニズム Spinal mechanisms underlying post-ischemic numbness ○渡部達範1,2, 駒形成司1, 塚野浩明1, 菱田竜一1, 河野達郎2, 馬場洋2, 澁木克栄1 ○Tatsunori Watanabe1,2, Seiji Komagata1, Hiroaki Tsukano1, Ryuichi Hishida1, Tatsuro Kohno2, Hiroshi Baba2, Katsuei Shibuki1 新潟大・脳研・生理1, 新潟大・医・麻酔2 Dept Neurophysiol, Brain Res Inst, Niigata Univ, Niigata, Japan1, Dept Anesthesiol, Sch Med, Niigata Univ, Niigata, Japan2 We experience numbness after transient ischemia of extremities. However, the mechanisms underlying this post-ischemic numbness are largely unknown. One possibility is a peripheral mechanism: ischemia induces failure in aerobic energy metabolism and the resulting depolarization and hyperexcitability in peripheral mechanoreceptors/sensory nerves. Another possibility is a spinal mechanism: conduction block of peripheral sensory nerves induces abnormal sensitization of the spinal neural circuits in our previous study. To investigate the mechanisms underlying the post-ischemic numbness, we recorded somatosensory cortical responses using transcranial flavoprotein fluorescence imaging in mice. The transient ischemia of the hindpaw was produced by application of high pressure into a rubber cuff set around the thigh for 30 min. Vibratory stimuli applied to the ischemic hindpaw produced no cortical responses. However, the cortical responses were quickly recovered after removal of the ischemia, and the responses were potentiated compared with those recorded before the ischemia, suggesting the presence of abnormal sensation corresponding to post-ischemic numbness. To our surprise, vibratory stimuli applied to the hindpaw contralateral to the ischemic hindpaw also produced potentiated cortical responses compared with the responses before ischemia. Cortical responses to forepaw stimulation, however, were not potentiated during and after ischemia of a hindpaw. Type II metabolic glutamate receptors (mGluRs) are involved in the abnormal sensitization of the spinal neural circuits after conduction block. LY354740, an agonist of type II mGluRs, applied to the surface of the spinal cord at L1 inhibited the post-ischemic potentiation of cortical response to ipsilateral hindpaw stimulation, and the potentiation of cortical response to contralateral hindpaw stimulation during ischemia. These results clearly indicate the presence of spinal mechanisms underlying post-ischemic numbness.	P3-1-143 生後発達期マウス視床における軸索起源と相関するシナプス刈り込み Somatotopic tuning along with synapse elimination in the whisker sensory thalamus of developing mice ○竹内雄一1, 宮田麻理子1,2 ○Yuichi Takeuchi1, Mariko Miyata1,2 東京女子医大・医・第一生理1, さきがけ・科学技術振興機構2 Dept Physiol, Tokyo Women's Med Univ, Tokyo1, PRESTO, Japan Science and Technology Agency, Saitama2 In the developing somatosensory thalamus of mice, several lemniscal fibers (sensory afferents) initially converge on a single relay neuron. Then, redundant lemniscal fibers are subsequently eliminated, so that typically only one lemniscal fiber survives on a mature relay neuron. However, qualitative differences between surviving and eliminated lemniscal fibers remained unexplored. One hypothesis suggested that somatotopic origins of surviving and eliminated lemniscal fibers are different. To test this hypothesis, we generated Krox20-Cre;Ai14 transgenic mice, where projection neurons in the maxillary subregion of the principle trigeminal nucleus specifically express cre recombinase and the cre then drives tdTomato expression. In this mice, whisker-related lemniscal boutons are characterized as tdTomato-labeled presynaptic puncta, tdT(+), whereas non-whisker-related lemniscal boutons be as tdT(-). Before the onset of synapse elimination, the thalamus had roughly the same proportions of tdT(+) and tdT(-) boutons. During the synapse elimination period, densities of both types of boutons decreased, but the proportion of tdT(+) boutons increased to well over 80%, indicating that tdT(-) boutons were more drastically eliminated. The biased elimination was more prominent in the septal region than in the barreloid hollow and more on dendrites than on soma of relay neurons. This result further contrasts the differences between surviving and eliminated fibers. Our results suggested that different origins of multiply innervating lemniscal fibers may be the cause of the nonrandom synapse elimination, and this process may underlie somatotopical information tuning in the developing circuit.
P3-1-144 in vivo 単一神経細胞電位記録による三叉神経一次感覚ニューロンの機能形態学的解析 Full visualization of single trigeminal ganglion neuron ○榎原智美1, 外村宗達1, 熊本賢三1, 黒田大地1, 古田貴寛2, 古江秀昌3, 歌大介3 ○Satomi Ebara1, Sotatsu Tonomura1, Kenzo Kumamoto1, Daichi Kuroda1, Takahiro Furuta2, Hidemasa Furue3, Daisuke Uta3, Ehud Ahissar4 明治国際医療大学 医学教育研究センター 解剖学教室1, 京都大学　大学院医学研究科　高次脳形態学教室2, 生理学研究所 生体情報研究系 神経シグナル研究部門3, ワイツマン科学研究所 神経生物学教室4 Dept Anatomy, Meiji Univ of Integrative Med, Kyoto, Japan1, Dept Morphological Brain Science, Graduate School of Medicine, Kyoto University, Kyoto, Japan2, Dept Information Physiology, Div Neural Signaling, National Institute for Physiological Science, Okazaki, Japan3, Dept Neurobiology, Weizmann Institute of Science, Rehovot, Israel4 Primary sensory neuron is a pseudomonopolar cell. We investigated whole structure of single trigeminal ganglion (TG) neurons including both terminations in addition to the physiological characteristics of responsibility. We tried in vivo intracellular recording and labelling in the rat TG neuron. Animal (Wistar rat, 3-5weeks old) was deeply anesthetized and the brain matter was cylindrically removed by suction to approach toward the TG. A glass electrode (20-50Mohm) filled with 15-20% neurobiotin in 1M potassium acetate was inserted to a TG neuron. After recording of firing spikes from appropriate receptive field (RF) in the facial skin, neurobiotin was electrophoretically injected. After survival time, the animal was perfused with 20% formalin. Labelled neuron was visualized by using biotin enhancing method. Labelled axon never branch until close to the RF since the TG. Each peripheral axon terminated showing only one type of endings. One of successfully visualized neurons showed only a single club-like ending. The labelled axon never branched to the end. The club-like axon terminal was distributed to a caudal position of the ringwulst in a large vibrissa. Slowly adapting firings were recorded by protraction of the vibrissa, that is, by bending it to rostral direction. In contrast, central single trunk axons of the neuron gave more than 20 lateral branches in a stepwise fashion throughout the elongated trigeminal nuclei.	P3-1-145 カチオンチャンネルのどのパラメタが機械受容器の特性を支配しているのか？ What parameters of cation channels dominate the characteristics of a mechanoreceptor? ○藤田一寿1,2 ○Kazuhisa Fujita1,2 電通大・先進理工1, 津山高専・情報2 Dept Engin Sci, Univ of Electro-Comm, Tokyo1, Tsuyama NCT, Okayama2 A mechanoreceptor in our skin receives a mechanical stimulus and convert the stimulus to spikes. There are various kinds of the mechanoreceptors. Those are hair follicles, Meisner corpuscle, Pacinian corpuscle, Merkel cell, Ruffini corpuscle, etc. Two types of mechanoreceptors can be distinguished generally. One is fast adapting (FA) receptor such as hair follicles, Meisner corpuscles, and Pacinian corpuscle. The other is slowly adapting (SA) receptor such as Merkel cells and Ruffini corpuscle. The kinetics of the mechanosensitive current of a mechanoreceptor is produced by activity of cation channels those are ion channels sensitive to mechanical force. The cation channels are on the ending of a mechanoreceptor and convert mechanical force to ion current. The difference of kinetics of the mechanoreceptors is considered to induced by cation channels that have various properties such as time constants and thresholds. The purpose of the present study is to develop a mechanoreceptor model considering recently experimental results and to find dominant parameter of cation channels. Mechanosensitive current of our mechanoreceptor model is generated by cation channels sensitive to mechanical stimulus. In this study, we calculated the mechanosensitive current with changing parameters of cation channels using our model. As the results of computer simulation using our model, the model could reproduce the kinetics of a real mechanoreceptor. Changing the time constant of cation channels, the proposed model provided output of a SA or FA receptor. Sensitivity of a mechanoreceptor depended on standard deviation and mean of the distribution of channel's own parameters.
P3-1-146 光学的膜電位測定によって観察されたラットバレル野第2/3層神経活動のGABAB受容体依存的ペアドパルス抑制 GABAB receptor-mediated paired-pulse depression of neuronal activities in the rat barrel cortex observed by a voltage-sensitive dye imaging method ○佐藤元1, 豊田博紀1, 齋藤充1, 姜英男1 ○Hajime Sato1, Hiroki Toyoda1, Mitsuru Saito1, Youngnam Kang1 大阪大学大学院歯学研究科高次脳口腔機能学講座口腔生理学1 Dept Neurosci & Oral Physiol, Osaka Univ Grad Sch Dent, Osaka1 It is reported that in the rat somatosensory cortex intracortical EPSCs evoked in layer 3 (L3) pyramidal cells by stimulation of L3 are suppressed by activation of presynaptic GABAB receptor (GABABR). Since intracortical EPSCs are involved in inter-columnar synchronization, it is possible that GABABR-mediated presynaptic inhibition (GABABR-Pre-I) of intracortical inputs is involved in inter-columnar desynchronization. We addressed this possibility in the rat barrel cortex by using a voltage-sensitive dye imaging method in slice preparations. When a paired microstimulation at 200-ms interval was applied to L2/3 of a column in the presence of bicuculline and APV, the horizontal spread of the excitation in L2/3 extended markedly beyond the distal end of the neighboring columns after the 1st stimulation, resulting in the excitation in L5 of the same columns that exhibited synchronous excitation in L2/3. The 2nd stimulation induced a weaker optical response. When the optical responses to the 1st and 2nd stimuli were compared, the horizontal excitation spread in L3 appeared to be depressed in the 2nd response. CGP55845 converted such a spatial PPD into a PPF, which resulted in a marked enhancement of the 2nd response in L5. This enhancement of excitation spread by CGP may be caused largely by a release from inter-columnar desynchronization because more synchronous activation of L2/3 PCs induces more activation of L5 PCs. Thus, GABABR-Pre-I is likely to be involved in the desynchronization of spike activities between the two neuronal populations in mutually adjacent columns, consistent with the previous observations made in two PCs by the simultaneous whole-cell recordings under voltage-clamp condition (Sato et al., 2012).	P3-1-147 伸展刺激誘発性カルシウム応答の解析による機械感受性一次求心性ニューロンの分類 Classification of mechanosensitive primary sensory neurons based on an analysis of unidirectional stretch-evoked calcium responses ○片野坂公明1, 高津理美2, 成瀬恵治2, 片野坂友紀2 ○Kimiaki Katanosaka1, Satomi Takatsu2, Keiji Naruse2, Yuki Katanosaka2 名古屋大・環境医学研究所・神経系II1, 岡山大学大学院医歯薬学総合研究科2 Dept Neurosci, RIEM, Nagoya Univ, Nagoya, JAPAN1, Dept Cardiovasc Physiol, Grad Sch of Med, Dent and Pharm Sci, Okayama Univ, Okayama, Japan2 Many distinct types of mechano-sensitive primary sensory neurons enable animals to detect a wide variety of mechanical information from innocuous to noxious range. Although several candidate molecules of mechanotransducer have been reported, the cellular and molecular mechanisms producing the variation in mechanosensitive neurons are still unclear. Here, we examined a stretch-evoked calcium response of mouse dorsal root ganglion neurons, and tried to classify the mechanosensitive neurons in terms of the kinetics of stretch response, cell size and chemical sensitivities. Dissociated sensory neurons were briefly cultured (<6 h) on an elastic silicone chamber and unidirectionally stretched by a motor-controlled device. The stretch response was measured by ratiometric calcium imaging with Fura-2. The stretch-evoked increase of intracellular calcium was observed in 17% of the neurons. Based on a rate of decay of a calcium rise, the stretch responses were subdivided into two types: fast-decay and slow-decay responses. The former response was largely decreased by ruthenium red, a broad-spectrum TRP (transient receptor potential) channel inhibitor, but the latter was not. Most of the neurons showing the fast-decay response have higher stretch threshold and small cell size, and responded to 2-aminoethoxydiphenyl borate and probenecid. On the other hand, neurons showing the slow-decay response have lower threshold and larger size, but did not respond to these chemicals. Thus, we found that stretch-sensitive primary sensory neurons were subdivided into at least two distinct populations. Based on their characteristics, each class of neurons showing fast-decay or slow-decay response would be high-threshold mechanonociceptors and polymodal nociceptors, or low-threshold mechanoreceptors involved in tactile sensation and proprioception, respectively. The results offer a new methodology to analyze mechanical responses of the primary sensory neurons.
P3-1-148 Dissociation of subjective peak timing between hot and cold stimuli Dissociation of subjective peak timing between hot and cold stimuli 佐藤克成2, 黒木忍1, 渡邊淳司1, 前野隆司2, 西田眞也1 ○Hsin-Ni Ho1, Katsunari Sato2, Scinob Kuroki1, Junji Watanabe1, Takashi Maeno2, Shin'ya Nishida1 , 慶應義塾大学2 NTT Communication Science Laboratories, Kanagawa, Japan1, Keio University, Kanagawa, Japan2 The ability to sense dynamic temperature stimuli is vital to our life. They signal the changes in environmental condition to heighten attention and behavioral reaction. It has been shown that human thermosensory system is extremely sensitive to a small change in temperature; however few empirical studies investigated the temporal characteristics of thermosensory system in response to dynamic temperature stimuli. In the present study, we investigated the timing difference between a dynamic temperature change and the resulting change in thermal sensation. We used a periodic thermal stimulation (sinusoid wave) whose baseline temperature was at 29, 33, or 37 degree C for cold, neutral or warm condition, respectively. We showed the sinusoid stimulation to participants and asked them to press a key in synchrony with the time of subjective temperature peak (i.e., when they perceived the sinusoid stimulation reaching the hottest or coldest temperature). We found that the temporal relationship between the physical and subjective peaks was different for warm and cold conditions. For warm condition, the subjective peak occurred after the physical peak (physically hottest temperature), in the phase where the stimulation temperature passed the hottest temperature and started to decrease. In the case of cold condition, on the other hand, the subjective peak occurred before the perceptual peak (physically coldest temperature), in the phase where the physical temperature was still on its way down to the coldest temperature. Our findings suggest that our sense of warmth acts something like an integrator, which sums up the thermal inputs over a temporal window to determine the maximum intensity, while our sense of cold is more like a differentiator, which determines the maximum intensity based on the transient temperature change.

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